Field of the Invention
Crankcase motor oil compositions are continuously being reformulated to meet increasingly severe service requirements. Lengthened oil drain intervals in one example of a more severe lubrication requirement. Engine design changes intended to reduce hydrocarbon emissions and exhaust emissions which involve such developments as positive crankcase ventilation and lean burn gasoline engines impose new stresses on the motor oil composition as a result of these engineering advances. At the same time, the anti-rust and anti-sludge forming characteristics of the lubricating oil composition must be maintained under all driving conditions including the relatively severe short trip, cold engine operation.
A further objective of crankcase oil development is to provide a motor oil composition which qualifies as a low-ash lubricant composition and yet maintains its effectiveness for neutralizing acidic blow-by products in the crankcase zone of the engine.
A number of nitrogen-boron-containing additives have been proposed for mineral lubricating oil compositions. The nitrogen-boron-containing lubricant additive of the present development constitutes a novel lubricant additive and it serves to significantly advance the performance of a low-ash lubricant composition as compared to a lubricant with a non-boron containing additive.